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author | Kostya Kortchinsky <kostyak@google.com> | 2019-06-18 17:41:17 +0000 |
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committer | Kostya Kortchinsky <kostyak@google.com> | 2019-06-18 17:41:17 +0000 |
commit | 63696db5559d8d9fac828309c2799daebba721ff (patch) | |
tree | a3c19f83c86441fe07db2917ffa95aeb1770877f /lib/scudo/standalone | |
parent | 7727012e5d946fd128274a41a4b159e990787ed2 (diff) | |
download | compiler-rt-63696db5559d8d9fac828309c2799daebba721ff.tar.gz |
[scudo][standalone] Fuchsia related changes
Summary:
Fuchsia wants to use mutexes with PI in the Scudo code, as opposed to
our own implementation. This required making `lock` & `unlock` platform
specific (as opposed to `wait` & `wake`) [code courtesy of John
Grossman].
There is an additional flag required now for mappings as well:
`ZX_VM_ALLOW_FAULTS`.
Reviewers: morehouse, mcgrathr, eugenis, vitalybuka, hctim
Reviewed By: morehouse
Subscribers: delcypher, jfb, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D63435
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@363705 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/scudo/standalone')
-rw-r--r-- | lib/scudo/standalone/fuchsia.cc | 32 | ||||
-rw-r--r-- | lib/scudo/standalone/linux.cc | 20 | ||||
-rw-r--r-- | lib/scudo/standalone/mutex.h | 23 |
3 files changed, 37 insertions, 38 deletions
diff --git a/lib/scudo/standalone/fuchsia.cc b/lib/scudo/standalone/fuchsia.cc index e54563138..cf0323819 100644 --- a/lib/scudo/standalone/fuchsia.cc +++ b/lib/scudo/standalone/fuchsia.cc @@ -14,8 +14,10 @@ #include "mutex.h" #include "string_utils.h" -#include <limits.h> // for PAGE_SIZE -#include <stdlib.h> // for getenv() +#include <lib/sync/mutex.h> // for sync_mutex_t +#include <limits.h> // for PAGE_SIZE +#include <stdlib.h> // for getenv() +#include <zircon/compiler.h> #include <zircon/sanitizer.h> #include <zircon/syscalls.h> @@ -90,7 +92,8 @@ void *map(void *Addr, uptr Size, const char *Name, uptr Flags, } uintptr_t P; - zx_vm_option_t MapFlags = ZX_VM_PERM_READ | ZX_VM_PERM_WRITE; + zx_vm_option_t MapFlags = + ZX_VM_PERM_READ | ZX_VM_PERM_WRITE | ZX_VM_ALLOW_FAULTS; const uint64_t Offset = Addr ? reinterpret_cast<uintptr_t>(Addr) - Data->VmarBase : 0; if (Offset) @@ -149,18 +152,21 @@ void releasePagesToOS(UNUSED uptr BaseAddress, uptr Offset, uptr Size, const char *getEnv(const char *Name) { return getenv(Name); } -void BlockingMutex::wait() { - const zx_status_t Status = - _zx_futex_wait(reinterpret_cast<zx_futex_t *>(OpaqueStorage), MtxSleeping, - ZX_HANDLE_INVALID, ZX_TIME_INFINITE); - if (Status != ZX_ERR_BAD_STATE) - CHECK_EQ(Status, ZX_OK); // Normal race +// Note: we need to flag these methods with __TA_NO_THREAD_SAFETY_ANALYSIS +// because the Fuchsia implementation of sync_mutex_t has clang thread safety +// annotations. Were we to apply proper capability annotations to the top level +// BlockingMutex class itself, they would not be needed. As it stands, the +// thread analysis thinks that we are locking the mutex and accidentally leaving +// it locked on the way out. +void BlockingMutex::lock() __TA_NO_THREAD_SAFETY_ANALYSIS { + // Size and alignment must be compatible between both types. + COMPILER_CHECK(sizeof(sync_mutex_t) <= sizeof(OpaqueStorage)); + COMPILER_CHECK(!(alignof(decltype(OpaqueStorage)) % alignof(sync_mutex_t))); + sync_mutex_lock(reinterpret_cast<sync_mutex_t *>(OpaqueStorage)); } -void BlockingMutex::wake() { - const zx_status_t Status = - _zx_futex_wake(reinterpret_cast<zx_futex_t *>(OpaqueStorage), 1); - CHECK_EQ(Status, ZX_OK); +void BlockingMutex::unlock() __TA_NO_THREAD_SAFETY_ANALYSIS { + sync_mutex_unlock(reinterpret_cast<sync_mutex_t *>(OpaqueStorage)); } u64 getMonotonicTime() { return _zx_clock_get_monotonic(); } diff --git a/lib/scudo/standalone/linux.cc b/lib/scudo/standalone/linux.cc index 5e695d72f..bfda03239 100644 --- a/lib/scudo/standalone/linux.cc +++ b/lib/scudo/standalone/linux.cc @@ -84,14 +84,22 @@ void releasePagesToOS(uptr BaseAddress, uptr Offset, uptr Size, // Calling getenv should be fine (c)(tm) at any time. const char *getEnv(const char *Name) { return getenv(Name); } -void BlockingMutex::wait() { - syscall(SYS_futex, reinterpret_cast<uptr>(OpaqueStorage), FUTEX_WAIT_PRIVATE, - MtxSleeping, nullptr, nullptr, 0); +void BlockingMutex::lock() { + atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage); + if (atomic_exchange(M, MtxLocked, memory_order_acquire) == MtxUnlocked) + return; + while (atomic_exchange(M, MtxSleeping, memory_order_acquire) != MtxUnlocked) + syscall(SYS_futex, reinterpret_cast<uptr>(OpaqueStorage), + FUTEX_WAIT_PRIVATE, MtxSleeping, nullptr, nullptr, 0); } -void BlockingMutex::wake() { - syscall(SYS_futex, reinterpret_cast<uptr>(OpaqueStorage), FUTEX_WAKE_PRIVATE, - 1, nullptr, nullptr, 0); +void BlockingMutex::unlock() { + atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage); + const u32 V = atomic_exchange(M, MtxUnlocked, memory_order_release); + DCHECK_NE(V, MtxUnlocked); + if (V == MtxSleeping) + syscall(SYS_futex, reinterpret_cast<uptr>(OpaqueStorage), + FUTEX_WAKE_PRIVATE, 1, nullptr, nullptr, 0); } u64 getMonotonicTime() { diff --git a/lib/scudo/standalone/mutex.h b/lib/scudo/standalone/mutex.h index 6de3810b4..58bc15898 100644 --- a/lib/scudo/standalone/mutex.h +++ b/lib/scudo/standalone/mutex.h @@ -57,34 +57,19 @@ private: void operator=(const SpinMutex &) = delete; }; -enum MutexState { MtxUnlocked = 0, MtxLocked = 1, MtxSleeping = 2 }; - class BlockingMutex { public: - explicit constexpr BlockingMutex(LinkerInitialized) : OpaqueStorage{0} {} + explicit constexpr BlockingMutex(LinkerInitialized) : OpaqueStorage{} {} BlockingMutex() { memset(this, 0, sizeof(*this)); } - void wait(); - void wake(); - void lock() { - atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage); - if (atomic_exchange(M, MtxLocked, memory_order_acquire) == MtxUnlocked) - return; - while (atomic_exchange(M, MtxSleeping, memory_order_acquire) != MtxUnlocked) - wait(); - } - void unlock() { - atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage); - const u32 V = atomic_exchange(M, MtxUnlocked, memory_order_release); - DCHECK_NE(V, MtxUnlocked); - if (V == MtxSleeping) - wake(); - } + void lock(); + void unlock(); void checkLocked() { atomic_u32 *M = reinterpret_cast<atomic_u32 *>(&OpaqueStorage); CHECK_NE(MtxUnlocked, atomic_load_relaxed(M)); } private: + enum MutexState { MtxUnlocked = 0, MtxLocked = 1, MtxSleeping = 2 }; uptr OpaqueStorage[1]; }; |